Spain coach Luis Enrique set each of his players the "homework" of practising 1,000 penalties ahead of the World Cup, saying he is convinced they are not a lottery.
The 2010 world champions face Morocco in the last 16 on Tuesday, with the threat of extra-time and penalties looming in the knockout phase of the tournament in Qatar.
Spain beat Switzerland on penalties at last year's Euro 2020 but were eliminated on spot-kicks by Italy in the semi-finals.
"Over a year ago, in one of the Spain camps, I told them they had to get here with at least 1,000 penalties taken," Luis Enrique said on Monday.
"I imagine that they have done their homework. If you wait until getting here to practise penalties... (it won't be enough).
The Spaniard insisted spot kicks were "not a lottery".
"It's a moment of maximum tension, a time to show your nerve, and that you can shoot the penalty in the way you have decided, if you have trained it a thousand times," he said.
"It says a lot about each player. It's trainable, manageable, how you manage the tension. It's increasingly less luck -- the goalkeepers have more influence.
"We have a very good goalkeeper, any of the three can do very well in this situation. Every time we finish training I see a lot of players taking penalties."
The Spain coach also responded to criticism over the team's style of play -- their commitment to playing out from defence sometimes puts them under pressure in dangerous areas.
Japan earned a shock 2-1 win over Spain, with their first goal coming after the European team lost the ball on the edge of their box and Ritsu Doan slammed home.
"Every team has their weapons," said Luis Enrique. "We want to get the ball in the best way possible to the forwards,"
"If we have to hit a long ball, we'll hit it. The interpretation has to be done on the pitch."
He said he did not agree with Spain's critics.
"It doesn't make sense to say that against Japan if we hoofed it away to clear our lines we wouldn't have let in the first goal," he said.
"We also wouldn't have scored any goals if we kept kicking it long. We will keep playing the ball out from the back, it's what we want."
Luis Enrique confirmed that Cesar Azpilicueta had recovered from his knock against Japan and all 26 players would be fit to train on Monday evening ahead of the game.
© Agence France-Presse